1. Field of the Invention
This invention relates to a 3-phase bridge converting circuit module sealed in a single in-line package (SIP) type package, and more particularly to a 3-phase bridge converting circuit module which can be mounted on a printed circuit (PC) board with a desired arrangement of outer leads.
2. Description of the related art including information disclosed under section 1.97-1.99.
A 3-phase bridge converting circuit module such as a 3-phase bridge inverter circuit includes six transistors. Any set of two out of the six transistors makes a pair to form three inverter circuits. The six transistors are mounted on a lead frame and sealed in a package. The six transistors mounted on the lead frame are arranged in the order of first, fourth, second, fifth, third and sixth transistors. That is, the outer leads connected to the respective transistors are not arranged to correspond to the order of generation of the output signals or the output stages. The first to sixth transistors are arranged in the order as described above in order to simplify the internal connection in the package. With this construction, the pattern of the lead frame can be simplified and the lead frame can be easily formed, and therefore this type of construction is widely used. In addition to the 3-phase bridge inverter circuit, this also applies to other 3-phase bridging converting circuit modules.
In general use, the SIP type package is often directly soldered on the PC board in order to reduce the number of manufacturing steps thus attaining a low manufacturing cost and reducing the size of the device. For the same reason, the SIP package of the 3-phase bridge inverter circuit is directly soldered on the PC board. However, as described before, the outer leads of the SIP type package are not arranged in the order of generation of the output signals. Therefore, when the SIP package is mounted on the PC board, the circuit pattern on the PC board will be complicated. Further, if the circuit pattern on the PC board cannot satisfy the circuit connection, it becomes necessary to additionally form a wiring connection using jumper lines such as short lead lines in addition to the circuit pattern on the PC board. Thus, the step for mounting the module on the PC board will be complicated.
Further, in the case where the first to sixth transistors (semiconductor elements) are large power elements in which a large current will flow, it will be necessary to use a wide wiring pattern as the circuit pattern on the PC board. However, if the circuit pattern becomes complicated, such a wide wiring pattern cannot be used. Therefore, it is difficult to use this type of 3-phase bridge inverter circuit for the large power elements.